A printed circuit board to which a localised solder connection is to be made, the surface of said printed circuit board having a continuous or non-continuous coating of a composition comprising a halo-hydrocarbon polymer at a thickness of from 1 nm to 10 \u03bcm. The reservoir has a housing of transparent material with measuring scales marked on the outside. This converted video signal is then provided for the alternative display terminal to accommodate the corresponding video display on a screen provided by the alternative display terminal. A plurality of flexible and resilient sealing devices contact a top surface of a workpiece. The optimum transmit power calculation unit adaptively updates a logarithm of the barrier parameter and uses a gradient obtained through a high-order derivative with the logarithm of the barrier parameter to calculate the transmit power level to optimize the resulting objective function.